1907.] GracnicJier, Pollination of Wisconsin Flowers. 85 
involved in the same process. At the beginning of this, the male 
stage of the flower's existence, the styles are very short, and the 
stigmas hardly noticeable. But the styles gradually rise above 
their surroundings, and after all the anthers have emptied their 
reddish-yellow pollen the small capitate stigmas become receptive. 
The female stage is therefore very plainly separated from the 
male stage, and in such a flower self-pollination is entirely out of 
the question. Cross-pollination is insured by the visits of numer- 
ous insects, and these obtain a bountiful supply of nectar and 
pollen. The individual flower is unsightly, but the grouping of 
such a large number as are usually present in the inflorescence of 
each plant renders the whole more or less attractive. Correspond- 
ing with the entirely exposed situation of the nectar we find these 
small flowers visited nearly exclusively by insects with short 
tongues. Several European species of Saxifraga are especially 
attractive to flies, but in our 5". Pcnnsyh anica other short-tongued 
insects are just as well represented, and the small bees of the 
genus Halictus are always regular attendants. According to the 
list given below the flies and short-tongued bees together represent 
64% of the entire number of visitors, and this agrees quite well 
with the figures obtained for other flowers with entirely exposed 
nectar. 
A. Hymenoptera. 
Apidae: (i) Apis mellifera L., worker, s. ; Andrenidse: (2) 
Andrena marice Rob., female, s. ; (3) Halictus pilosus Sm., 
female, s. and c. p.; (4) H. zephynis Sm., female, s. and c. p.; 
(5) H. sparsus Rob., female, s. and c. p.; (6) H. hortensis Lov., 
female, s. and c. p.; (7) H. anomalus Rob., female, s. and c. p.; 
(8) Sphecodes cressonii Rob., female, s. ; (9) vS. arvensis Patton, 
female, s. ; (10) Prosopis pygmwa Cr., male, s. ; Eumenid^: (11) 
Odynerus philadelphiw Sauss., s. ; Crabronidae: (12) Crahro 
obsciirus Sm., s. ; (13) C. trifasciatus Say, s. ; (14) Oxyhelus 
4-notatiis Say, s. ; Ichneumonidse : (15) Ichneumon sp., s. ; (15) 
Cryptus persimilis Cr., s. ; (17) Cryptiis sp., s. ; (18) Chorimeus 
carinatus Cr., s. ; Tenthredinidse : (19) Dolerus similis Norton, s. ; 
(20) D. aprilis Norton, s. 
